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js/geometry/GeometryRect.js

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+import GeometryPoint from "./GeometryPoint.js";
+import GeometryStroke from "./GeometryStroke.js";
+import GeometryPointCollection from "./GeometryPointCollection.js";
+
+export default class GeometryRect
+{
+    /**
+     * @param x: float
+     * @param y: float
+     * @param width: float
+     * @param height: float
+     */
+    constructor(x, y, width, height)
+    {
+        this.position = new GeometryPoint(x, y);
+        this.width = width;
+        this.height = height;
+    }
+
+    /**
+     * Returns if the given point is inside this rect.
+     *
+     * @param geometryPoint
+     * @returns {boolean|boolean}
+     */
+    isContainingPoint(geometryPoint)
+    {
+        let containsHorizontally = geometryPoint.x >= this.position.x && geometryPoint.x <= this.position.x + this.width;
+        let containsVertically = geometryPoint.y >= this.position.y && geometryPoint.y <= this.position.y + this.height;
+
+        return containsHorizontally && containsVertically;
+    }
+
+    getBorderTop()
+    {
+        return new GeometryStroke(
+            new GeometryPoint(this.position.x, this.position.y),
+            new GeometryPoint(this.position.x + this.width, this.position.y)
+        );
+    }
+
+    getBorderLeft()
+    {
+        return new GeometryStroke(
+            new GeometryPoint(this.position.x, this.position.y),
+            new GeometryPoint(this.position.x, this.position.y + this.height)
+        );
+    }
+
+    getBorderRight()
+    {
+        return new GeometryStroke(
+            new GeometryPoint(this.position.x + this.width, this.position.y),
+            new GeometryPoint(this.position.x + this.width, this.position.y + this.height)
+        );
+    }
+
+    getBorderBottom() {
+        return new GeometryStroke(
+            new GeometryPoint(this.position.x, this.position.y + this.height),
+            new GeometryPoint(this.position.x + this.width, this.position.y + this.height)
+        );
+    }
+
+    /**
+     * Returns all intersection points between this rect and a line.
+     *
+     * @param geometryLine
+     * @returns {GeometryPointCollection}
+     */
+    getBorderIntersectionsWithLine(geometryLine)
+    {
+        let borders = [
+            this.getBorderTop(),
+            this.getBorderLeft(),
+            this.getBorderRight(),
+            this.getBorderBottom()
+        ];
+
+        let intersections = new GeometryPointCollection();
+
+        borders.forEach(
+            (border) => {
+                let intersection = border.getIntersectionWithLine(geometryLine);
+
+                if (intersection !== null && this.isContainingPoint(intersection)) {
+                    intersections.addGeometryPoint(intersection);
+                }
+            }
+        );
+
+        return intersections;
+    }
+
+    getBorderIntersectionsWithStroke(stroke)
+    {
+        let borders = [
+            this.getBorderTop(),
+            this.getBorderLeft(),
+            this.getBorderRight(),
+            this.getBorderBottom()
+        ];
+
+        let intersections = new GeometryPointCollection();
+
+        borders.forEach(
+            (border) => {
+                let intersection = border.getIntersectionWithStroke(stroke);
+
+                if (intersection !== null && this.isContainingPoint(intersection)) {
+                    intersections.addGeometryPoint(intersection);
+                }
+            }
+        );
+
+        return intersections;
+    }
+
+    /**
+     * Get all intersections between this and another rect as point collection.
+     *
+     * @param rect GeometryRect
+     * @returns {GeometryPointCollection}
+     */
+    getBorderIntersectonsWithRect(rect)
+    {
+        let intersections = new GeometryPointCollection();
+
+        let strokes = [
+            rect.getBorderTop(),
+            rect.getBorderLeft(),
+            rect.getBorderRight(),
+            rect.getBorderBottom(),
+
+        ];
+
+        strokes.forEach(
+            (stroke) => {
+                this.getBorderIntersectionsWithStroke(stroke).forEach(
+                    (point) => {
+                        intersections.addGeometryPoint(point);
+                    }
+                )
+            }
+        );
+
+        return intersections;
+    }
+
+    /**
+     * Returns the four points that define the edges of this rect.
+     *
+     * @returns {GeometryPointCollection}
+     */
+    getRectanglePoints()
+    {
+        let collection = new GeometryPointCollection();
+
+        collection.addGeometryPoint(this.position);
+        collection.addGeometryPoint(new GeometryPoint(this.position.x + this.width, this.position.y));
+        collection.addGeometryPoint(new GeometryPoint(this.position.x, this.position.y + this.height));
+        collection.addGeometryPoint(new GeometryPoint(this.position.x + this.width, this.position.y + this.height));
+
+        return collection;
+    }
+
+    /**
+     * Returns the intersection area between this and another rect as new rect or null.
+     *
+     * @param rect GeometryRect
+     * @returns {null|GeometryRect}
+     */
+    getRectIntersection(rect)
+    {
+        let intersectionPoints = new GeometryPointCollection();
+
+        this.getRectanglePoints().forEach(
+            (point) => {
+                if (rect.isContainingPoint(point)) {
+                    intersectionPoints.addGeometryPoint(point);
+                }
+            }
+        );
+
+        if (intersectionPoints.getLength() >= 4) {
+            return intersectionPoints.getRect();
+        }
+
+        rect.getRectanglePoints().forEach(
+            (point) => {
+                if (this.isContainingPoint(point)) {
+                    intersectionPoints.addGeometryPoint(point);
+                }
+            }
+        );
+
+        if (intersectionPoints.getLength() >= 4) {
+            return intersectionPoints.getRect();
+        }
+
+        this.getBorderIntersectonsWithRect(rect).forEach(
+            (point) => {
+                intersectionPoints.addGeometryPoint(point);
+            }
+        );
+
+        if (intersectionPoints.getLength() >= 2) {
+            return intersectionPoints.getRect();
+        }
+
+        return null;
+    }
+
+    /**
+     * Visualizes the rect.
+     *
+     * @param context Context
+     * @param color string
+     */
+    draw(context, color = 'red')
+    {
+        context.fillStyle = color;
+        context.fillRect(this.position.x, this.position.y, this.width, this.height);
+        this.getBorderTop().draw(context);
+        this.getBorderLeft().draw(context);
+        this.getBorderRight().draw(context);
+        this.getBorderBottom().draw(context);
+    }
+
+}